Sanitizable signatures allow a designated entity to modify some specific parts of a signed message and to produce a new signature of the resulting message without any interaction with the original signer. In this paper, we extend these sanitizable signatures to formally introduce trapdoor sanitizable signatures. In this concept, the power of sanitization is given to possibly several entities, for a given message/signature by using a trapdoor computed by the signer at any time. We also give a… CONTINUE READING